Heroku App is Reading database.yml File

Question

From what I can gather, Heroku is supposed to generate a database.yml file automatically, and ignore the local one. However, I am seeing an error where that is not true, and my changes to the local database.yml are affecting the Heroku app. This is problematic because I have no idea how I should setup production portion of the file so Heroku can find the right database.

For instance with the following

production: 
    adapter: sqlite3 
    database: db/production.sqlite3 
    pool: 5 
    timeout: 5000

followed by the db:migration

$:~/Apps/DancingCupid/DancingCupid$ heroku rake --trace db:migrate

spits out

rake aborted!
unable to open database file
/app/.bundle/gems/ruby/1.8/gems/activerecord-3.0.5/lib/active_record/connection_adapters/sqlite3_adapter.rb:27:in `initialize' 
...

I can get different errors depending on what type of database I sent for production.

Besides deleting the app and making a new one, is there a way to fix this problem?

Answer 1

Heroku definitely rewrite your database.yml on push so it doesn't matter what is in there in source control.

To confirm this do heroku run bash which will connect you to a bash session in your app then look do a cat config\database.yml and you will see how they have rewritten it.

Answer 2

The other answers are NOT TRUE anymore as of Rails 4.1.

config/database.yml won’t be overwritten anymore when a Rails 4.1.0 RC1 app is detected. Instead, it will be merged with DATABASE_URL so additional options like pool size can be set in config/database.yml.

To double-check the contents of your database.yml on the Heroku server, you can run remote bash via heroku run bash and then cat config/database.yml to see its contents on the server and compare with your local one.